Coronaviruses are a class of enveloped RNA viruses that live in many places, including humans, other mammals, and birds. To date, six coronaviruses have been found to infect humans [11]. There was a serious outbreak of SARS-CoV in China between 2002 and 2003 [12, 13]. MERS-CoV also led to a serious epidemic in the Middle East in 2012, and caused mass mortality [14]. Cross-species infection and occasional spillover events may lead to the recurrent emergence of new coronaviruses [15]. In December 2019, Wuhan city in Hubei province of China became an epicenter of the new coronavirus outbreak. As of 24 February 2020, the confirmed people infected with COVID-19 were 79 331, including 2069 people across 29 other countries [5]. These figures are being updated and increasing daily.
During the work of treating COVID-19 patients, we observed peculiar differences of our patients’ clinical features from those reported in early cases in Wuhan city. We had 50 patients who had recovered and got discharged. According to our data, none of the infected patients at our teaching hospital had been exposed to the Wuhan city seafood wet market, instead, 29 patients had a history of familial cluster interactions which strongly suggested human to human transmission. At present, the primary source of infection appears to be from the COVID-19 patients as well as the asymptomatic ones. Respiratory and close contact transmission are the main modes of transmission. In this vein, aerosol propagation may pose a grave risk of transmission, especially to those exposed to high concentrations of aerosols for a relatively long period of time in a confined environment [10]. Therefore, containment procedures such as quarantine, avoiding close contacts with suspected or infected people as well as mass health education, avoiding large gatherings and taking precautionary measures against exposure to COVID-19 should continue to be implemented to prevent large scale spread.
Compared with the initial patients infected in Wuhan city [6], the symptoms of patients in Wenzhou city are relatively mild. Wenzhou patients’ initial symptoms included fever, coughing, fatigue or muscle pain, pharyngalgia, diarrhea and rarely chest pain and headache. Atypical initial symptoms also deserve particular attention. For example, there were 3 patients with COVID-19 who presented with diarrhea as the initial symptom at disease onset in this study. Such observations are important because they point to clinicians being alert to the potential of misdiagnosis and differential diagnosis follow up. Among the Wenzhou patients, the median time from onset of symptoms to first hospital admission was relatively shorter. The news of the epidemic was now widely publicized officially by the Chinese government, as such these patients were very concerned about their health status and hence these early health-seeking behaviors. This could be the reason why the patients in the current study had relatively mild clinical symptoms. None of them was admitted to the hospital for breathing difficulties, a sign of severe disease progression. Early intervention in the treatment of COVID-19 pneumonia increases the likelihood of better prognosis among patients.
Viral nucleic acid detection using RT-PCR is the current standard. Non-contrast chest CT scans should also be considered for early diagnosis of this viral disease. Fang et al, reported that 50/51 (98%) patients had evidence of abnormal CT findings compatible with viral pneumonia at baseline while one patient had a normal CT. Such an observation was also confirmed in the current study. Of the 50 patients with abnormal CT results in Fang and colleagues’ study, 36 (72%) patients had typical CT scan manifestations (e.g. peripheral, subpleural ground-glass opacities, often in the lower lobes). In addition, difference in the detection rate on the initial CT scan (50/51 [98%, 95% CI 90–100%]) was significantly greater than observed from the first RT-PCR (36/51 [71%, 95%CI 56–83%]) (p < .001) [16]. Chung et al, also reported that the chest CT scans of 3 out of 21 patients were negative for viral COVID-19 pneumonia at initial presentation [17]. On the other hand, Xie et al reported that 5 out of 167 (3%) patients had negative RT-PCR results for COVID-19 at initial presentation despite having chest CT scan findings typical of viral pneumonia [18]. In our data, the sensitivity of first chest CTs (early phase, 0–2 days) was 85.9% (55/64), the sensitivity of the RT-PCR was 56.3% (36/64) demonstrating that early chest CT scanning was more sensitive than the initial RT-PCR (p < .001). There are some possible reasons for this: 1) the specificity and sensitivity of the detection technique itself are not good enough; 2) variation in the detection rate of kits from different manufacturers; 3) low patient viral load; or 4) improper clinical sampling [16]. We support the view that chest CT scans should be used as part of routine examination of COVID-19 Pneumonia at admission, especially when RT-PCR test results are negative.
The health statuses of patients with COVID-19 sometimes change very rapidly. This may be related to many factors such as treatment plan and patient’s premorbid physique as well as preexisting chronic diseases such as hypertension and diabetes. In clinical practice, some patients do have recurrent symptoms and suddenly slide into acute respiratory distress syndrome or multiple organ failure even after a relatively stable period of time. This phenomenon is thought to be related to the "cytokine storm syndromes" in the patient's body [19]. Although there are currently no vaccines or any known special cure for this disease, the treatment regimens provided for in the guideline for treating the novel coronavirus pneumonia [10] were able to increase the number of recovering patients, prevent deaths and shorten hospital stay. A lot of pathological changes could be happening in the lesioned lungs of the patients. The temporal characteristics observed on the initial CT imaging as we all as on follow up scans COVID-19 patients is a rich data source of the novel disease’s pathogenesis. In most of these discharged cases, the early stage of admission (0–5 days) chest CT usually shows Ground-Glass Opacities (GGO) and Consolidation [20]. However, with the progression of the disease, the GGO lesions gradually decrease, and consolidation increases at first and then remains relatively stable for some days. If the patient's condition gets controlled and improves, at the last stage of the disease, chest CT scans often show different degrees of pulmonary fibrosis in the lungs. This trend could help clinicians to make correct judgments which are good for the resolution of the disease. The characteristics, including temporal CT changes among COVID-19 patients, can provide a lot of important information that feeds into clinical decision making.
In the absence of effective drugs against COVID-19, the diagnosis and treatment protocol for novel coronavirus pneumonia manual continues to inform practice and would also benefit from data such as generated in this study for its future revisions. Previously, the large-dose glucocorticoids used to treat SARS caused some serious adverse reactions [21] and also failed to effectively decrease the mortality rate associated with the disease [22]. In light of this, we treated the patients with lower dose (30–80 mg/day) and for a shorter time (3–5 days) using methylprednisolone to alleviate the pulmonary exudates and inhibit a possible cytokine storm syndromes. However, the impact of such an adaptation requires further studies.